Apparatus for heating comminuted molding material



May 5, 1953 c. A. NICHOLS ET AL 2,637,070

APPARATUS FOR HEATING COMMINUTED MOLDING MATERIAL original Filed sagt. 17. 1947 l2 Sheets-Sheet l May 5, 1953 c. A. NICHOLS ET A1. 2,637,070

i APPARATUS FOR HEATING COMMINUTED MOLDING MATERIAL Original Filed Sept. 17. 1947 12 Sheets-Sheet 2 :wu/fw A. fun/fm May 5, 1953 c. A. NICHOLS ETAL v 2,637,070

APPARATUS FOR HEATING COMMINUTED MOLDING MATERAL Original Filed Sept. 17. 1947 12 Sheets-Sheet 3 May 5, 1953 c. A. NICHOLS ETAL 2,637,070

APPARATUS FOR HEATING COMMINUTED MOLDING MATERIAL Original Filed Sept. 17. 1947 12 Sheets-Sheet 4 May 5, 1953 c. A. NlcHoLs Erm. 2,637,070

APPARATUS FOR HEATING COMMINUTED MOLDING MATERIAL Original Filed Sept. 17. 1947 l2 Sheets-Sheet 5 I mf-m May 5, 1953 c. A. NlcHoLs :a1-A1. 2,337,070

APPARATUS FOR HEATING COMMINUTED MOLDING MATERIAL Original Filed Sept. 17. 1947 12 Sheets-Sheet 6 May 5, 1953 c. A. NlcHoLs ETAL 2,537,070

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May 5, 1953 c. A, NICHOLS ETAL 2,637,070

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APPARATUS RoR HEATING CQMMTNUTRD MOLDTNG MATERIAL original Filed s ept. 17. 1947 12 Sheets-Sheet l0 May 5, 1953 c. A. NICHOLS ETAL 2,637,070

APPARATUS FOR HEATING coMMINUTEn MOLDTNG MATERIAL Original Filed Sept. 17. 194'7 12 Sheets-Sheet ll May 5, 1953 c. A. NlcH-oLs ET AL APPARATUS FOR HEATING COMMINUTED MOLDING MATERIAL l2 Sheets-Sheet l2 Original Filed Sept. 17. 1947 Patented May 5, 1.953

APPARATUS FOR HEATING COMMINUTED MOLDING MATERIAL Charles A. Nichols, Anderson, Max E. Todd, Windfall, William A. Fletcher, Daleville, and Clarence J. Keller, Anderson, Ind., assignors to General Motors Corporation, Detroit, Mich., af

corporation of Delaware Original application September 17, 1947, Serial No. 774,592. Divided and this application April 7, 1950, Serial No. 154,654

6 Claims.

This application is a division of application, Serial No. 774,592, led September 17, 19417, now Patent No. 2,531,524.

vThis invention relates to the art of molding plastic materials.

An object of the present invention is to provide apparatus for preheating molding material while in comminuted form for use by an injection molding machine which receives the preheated comminuted material and causes it to be forced into mold cavities and therein to be cured under heat and pressure. The disclosed embodiment of the invention provides a hopper for receiving molding material, a device which distributes a predetermined quantity of material from the hopper in a layer upon a heated roller from which the heated material is removed and is caused to gravitate into a compression chamber of an open molding die of the molding machine. A companion molding die is caused to be pressed against the die having the compression chamber and the preheated material therein is forced by a piston or ram out of the compression chamber through ducts or runners connected with the die cavities in which the material is cured under heat and pressure.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment `of the present invention is clearly shown.

In the drawings:

Fig. 1 is a iront elevation of the molding machine and material handling apparatus.

Fig. 2 is a side elevation looking in the direction of arrow 2 of Fig. 1.

Fig. 3 is a fragmentary View partly in side elevation and partly in section, the section being taken on the line 3 3 of Fig. 1.

Fig. 4 is a fragmentary sectional view showing a portion of Fig. 3 on a larger scale. Y

Fig. 5 is a side elevation looking in the direc tion of arrow '5 of Fig. 1.

Fig. 6 is a plan View of the preheating apparatus.

Figs. 7 and 8 together form a front View of the preheating apparatus.

Fig. 9 is a side View looking in the direction of the arrow 9 of Fig. 6.

Fig. 10 is a fragmentary sectional view on line III-I0 of Fig. 9.

Figs. 11 and 12 together form a sectional view on line of Fig. 6'.

Fig. 13 is a fragmentary view in the direction of arrow I3 of Fig. 11.

Fig. 1s is a side view looking in the directionl of arrow I6 of Fig. 6.

Fig. 17 is a side view of a hopper looking in the direction of arrow of Fig. 7.

Fig. 18 is a fragmentary sectional View on line IS-l of Fig. 19.

Fig. 19 is a fragmentary sectional View on the line iS--IS of Fig. 16.

Fig. 20 is a front View of the roller cleaner assembly.

Fig. 21 is a sectional view on line 2|-2l of Fig. 20.

Fig. 22 is a front view of the roller scraper assembly.

Fig. 23 is a sectional view on line 23-23 of Fig. 22.

Fig. 24 is a fragmentary sectional view on line 24-24 of Fig. 11.

Fig. 25 is a fragmentary sectional View on line 25-25 of Fig. 9.

Fig. 26 is a fragmentary sectional view on line 26-26 of Fig. 11.

Fig. 27 is an enlarged sectional View of that portion with dot-dash rectangles 27.1` of Fig. 11.

Referring to Figs. 1, 2 and 5, the machine comprises a base |00 supporting posts li and |62 which support a bar |69 which supports a cylinder Il attached to the bar |09 by screws as shown in Fig. 3. Each of the posts and 62 is attached to the bar |9 in the manner shown in Fig. 3. The threaded end of each post receives a nut |2 received by a counterbore in the bar |09. When the nut ||2 is tightened, the bar |09 is clamped against a Washer H3 which, in turn, is clamped against a shoulder of the post. The cylinder lll receives a piston not shown attached to a rod |15 (Fig. 3) threadedly connected with two lower dies |22, |23 mounted on an oscillatable table |25.

The dies |22, |23 are secured to their respective supports by angle bars |24 and screws |24a.

A cylinder is attached to the table |25 and encloses a piston not shown. The movements of the table '|25 causes a lower die, such as |22,

Screws ||9 attach al1 of,

to be located under the upper die |21, while the other lower die E23 is located in a position for unloading the molded parts and reloading the die with inserts, when required, and with molding powder which has been preheated in a manner to be described.

The function of the cylinder ||0 (Fig. 2) is to contain the pressure fluid which raises and lowers its piston therein (not shown) which causes the upper die |2| to be pressed firmly against a lower die |22 before plastic material is forced into the mold cavities. The function of the cylinder |39 is to contain the pressure fluid which effects the movements of its piston which, through its connection with a compression ram not shown causes plastic material to be compressed in a cylinder not shown in the lower dies |22 and |23 and to flow therefrom through runners to the die cavities. The relation of the cylinder to the dies is shown and described in Serial N o. 174,592 referred to. The upper die 12| is maintained forcibly against a lower die while plastic material therein 1s being cured under pressure and heat supplied by the heating elements within the dies. After the curing cycle, the die beneath the upper die |2| is moved by rotation of the table |25 intov a position for unloading and reloading and it is replaced by a loaded lower die.

The apparatus for preheating the molding material comprises a bracket 333 attached to frames 33| and 332 (Figs. 6, 7, 8, 9, ll) which provide bearing holder half-shells 333 which support bearings 334 retained by bearing holder caps 305 attached to part 333. Bearings 334 support a shaft 303 connected by couplings 331 and 333 with a shaft 333 passing through an oil seal 3|0 and journaled in bearings 3|| and 3|2, supported respectively by a plate 3|4, a gear housing. 3|5 and a plate 3|6 which are attached together, the housing 3|5 being integral with a bracket 3 I 1 attached to frame 33| which supports another bracket 3|3 attached to housing. 3|5. Housing 3|5 encloses a worm gear 323 attached to shaft 303 and a worm 32| meshing with gear 320 and integral with a shaft 322 which is supported by bearings 323 and 324 (Fig. 9) carried respectively by a cap 325 and housing 3|5 and extending through an oil seal 325 ina cap 321. Shaft 322 is connected with a pulley 333 which a belt 33| connects with a pulley 332 on the shaft 333 of a motor M3 which is supported by a table 335 having ears 333 which a rod 331 pivotally connects with ears 333 of a bracket 333 which, like bracket 300, is supported by the molding machine. The belt 33| is tightened by turning a screw 34|)y threaded through bracket 339 and engaging the table 335, the screw 340 being fixed by a lock. nut 34| (Fig. 7). So long as motor M3 operates, the shaft 333 rotates.

Shaft 306 supports and drives a` heated steel cylinder 353 having a polished chromium surface on which the molding material is deposited and heated. Cylinder 353 is driven by pins 35| connected with a collar 352 welded to` shaft 305. The ends of cylinder 35|) are thermally insulated by transit rings 353, 354 and 355 in direct engagement with the cylinder 35|) which. supports also a transit ring 356 and disc 351 Which enclose electrical connectors comprising copper rings 358 and 359 which wires 330 and 36|, respectively, connect with collector rings 332 and 333 and a wire 364 connected with ring 365 and with a thermal switch 366 in the cylinder 353. Rings 358 and 359 are connected, respectively, with the terminals of heating element 361 as shown in Fig. 11. Collec- 4 tor rings 362, 353 and 365 are supported by and driven by shaft 335 and are insulated therefrom by discs 358, 363 and 310 clamped between washers 31| and 312 by a nut 313 threaded on shaft 306. Rings 332, 353 and 355 are engaged by brushes 314, 315 and 316 respectively, supported by non-conducting blocks 311 and 318 supported by a bracket 319 attached to frame 332 (Fig. 16).

The frames 33| and 332 together with the bracket 333 and a bar 33|? (attached to frames 33| and 332) provide a pocket for a hopper 33| having ribs 332 and 383 (Fig. 6) received by grooved bars 334 and 385, respectively, attached to frames 30| and 332 respectively. These ribs bottom in the lower ends of the grooves of the bars to support the hopper. The molding material gravitates. through an opening 333 (Fig. 14.-) in the bottom of the hopper and between a flange 331 provided by the hopper rear wall and a flange 338 of a plate 333 attached to lugs 333 pivoted on studs 39| attached to the hopper side walls. Plate 333 has ears 392, through the arcuate slots 333 thereof, there pass screws 334 threaded into the housing side walls. By loosening the screws 394, the flange 338 can be adjusted vertically to determine the thickness of the layer of material deposited upon a spreader roller 1133.

Spreader roller 493 is straight-knurled longitudinally with V-grooves about 3%" deep. It r0- tates counterclockwise (Fig. 14.) and carries the molding material from between the flanges 331 and 323 and drops it upon the heated cylinder 353 in an even layer. As the cylinder 353 rotates counterclockwise, the material is heated and it' softens sufficiently to cause the particles to stick together or to the roller so that it does not drop` from the roller until removed by av scraper 43| clamped by a bar 432 (Fig. 23) against a bar 433 attached to arms 434 pivoted on pins 435 supported by frames 33| and 302 (Fig. 22). Springs 406, connecting studs 431 on these frames with studs 438 on. the arms 434, urge the scraper 43| against the cylinder 353.

The material removed by the. scraper gravit'ates into a funnel 4|@ attached to arms 4|| (Fig. 16) pivotally supported by frames 30| and 302.. As shown in Fig. 19, one of the arms 4|| is attached to a shaft 4 2 journale'd in a bearing 4 I3 supportedby frame 332 and a fixed ratchet ring 4 I4 having teeth 4|5 engaging `teeth in a ring 41B which av spring 4|1 urges toward ring 4m. Shaft 4|2 carries a pin 4|8 received by slots 4| 9 in ring 4|6. When shaft 4|2 is turned by lever 423 having' a handle 42|r the ring M6 snaps longitudinally as its teeth are cammed out of the tooth space between the teeth 4|5 and then jump into said tooth spaces when aligned therewith. This ratchet or detent construction provides for maintaining the shaft 4|2 and supported funnel 4|0 in a desired position, one of which would be as shown when lling a mold as required and the other of which would be in a position away from the mold When unloading the molded parts and when cleaning the mold and when placing in the mold metal inserts when used.

The cylinder 353A is engaged by a cleaner bar 425, preferably of laminated` cloth with a Bakelite binder. Bar 425 is clamped by a bar 426 (Fig. 21) against a bar 421 having arms 428 pivotally supported on pins or screw studs 425 attached to frames 33| and 332. Each arm 428 is welded to a bar 430 carrying a stud 43| engaged by a hook -432 on a rod 433 which, as shown in Fig. 25, passes through a tube 434 attached to a frame 33| or 3'02, and is threaded into a nut 435. A spring 13G located between the nut 435 and a shoulder ttl of the tube urges the rod 233 upwardly to force the cleaner bar 425 against the cylinder. Thus the cylinder presents a clean surface to the fresh deposit of molding material. This minimises the possibility of delivery to the mold of any material which is cured beyond the predetermined stage of partial cure which the cylinder 35d is intended to accomplish.

The cylinder 35d and material carried thereby and dropping therefrom are enclosed by the side frames, a bar istil (liig. 14) attached thereto and a cover liti attached to lugs lllii pivotally supported by pins M3 attached to the side frames. A bar Mill connects the bottom rear edges of the side frames.

The amount oi the charge of molding material for a mold is determined in part by the distance of the ilange 383 (Fig. 14) above the roller ddii and by the duration of roller Mill. The transfer of material by the roller to the cylinder 35d is called dosing and the apparatus which controls the duration of rotation of roller lili? during each cycle of operation is called the doser.

Referring to Fig. ll, bearings 45d supported by the frames Siti and 332 and retained by rings 5ta support the roller i063 which carries a pin liti connected with a clutch part 452 having teeth ld engageable with similar teeth of a shiftable clutch part ddii attached to a gear 1155 meshing with a gear ll meshing with a gear ibi integral with coupling 363B. Gear i355 is pivoted on a rod fide (Fig. l0) attached to a bracket M59 supported housing bracket 3H (Fig. ll) Gear 45t is retained by a washer dta and a screw di threaded into rod 458. A groove 465 in clutch part receives pins itt of a yolre Mil welded to arms i358 and diie. Arm 46c is pivoted on a screw iid threaded into bracket 3H and has a hole lill (Fig. 24) which receives a screw i12 threaded into frame 33t and retained in the required positions of adjustment by a nut H3. The head of screw 113 limits counterclocliwise rotation of arm d68 under the effect of a compression spring 414 located between arm 459 and frame 3M and retained by pins 475 in each. Arm 468 is connected by pin 416, link Lili and pin li'l with the armature tlg of a solenoid it whose coil is known as the doser coil. When the coil is energized, the clutch parts 452 and 45d are connected and when the coil is deenergized, the spring 4M separates these clutch parts and the shaft i stops practically immediately because a brake is always effective. This brake, shown in Fig. 13, comprises a drum 13185 engaged by a. split band 186 having a hole Iil which receives a locating screw 488. rEhe band is urged against the drum by a spring 89 pushing against a washer 490 and the latter against the head of a screw 159i threaded into a nut i9 la which is urged by the spring 485i against one part of the band while the spring pushes directly against the other part of the band.

The cylinder heaters 367 are connected through slip rings 362, 3dS, 365 engaged, respectively, by brushes 3M, 315, 3l@ with a current source and with a heat regulating apparatus in a manner disclosed in application Serial No. 774,592. The heat regulating apparatus cuts off the heaters when the temperature of cylinder 350 exceeds a certain amount and closes circuit to them when cylinder temperature falls below a certain amount. A timing mechanism disclosed in said apparatus controls the starting and the duration of the operation of the doser through control of aesao'zo.

solenoid 48e. The quantity of the dose or charge of heated material supplied to the open mold is determined by the duration of operation of the doser and the material layer thickness on the spreader roller Mill by adjustment of plate 389 (Fig.14).

yWhile the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

l. For use with an injection molding machine having a compression chamber, a doser comprising a hopper containing a supply of comminuted molding material. a rotating roller, means for heating the roller, a longitudinally grooved, rotatable roller positioned between the hopper and the rotative heated roller for receiving material gravitating from the hopper and depositing it upon the heated roller, means for removing heated material from the heated roller, means for guiding the material heated by the heated roller into the compression chamber of the molding machine, means for determining the thickness of the layer of material conveyed by the grooved roller to the heated roller and means for controlling the duration of rotation of the grooved roller.

2. For use with an injection molding machine having a compression chamber, a doser comprising a hopper containing a supply of comminuted molding material, a rotating roller, means for heating the roller, a longitudinally grooved, rotatable roller positioned between the hopper and the rotative heated roller for receiving material gravitating from the hopper and depositing it upon the heated roller, means for removing heated material from the heated roller, means for guiding the material heated by the heated roller into the compression chamber of the molding machine, means for determining the thickness of the layer of material conveyed by the grooved roller to the heated roller, a motor for driving the heated roller, a clutch for connecting the motor with the grooved roller and means for controlling the clutch.

3. For use with an injection molding machine having a compression chamber and comprising a, frame having Vertical side members spaced apart a distance for receiving the widest of a series of hoppers of diierent widths, each adapted to be supported by the frame and each provided with an elongated opening at the bottom thereof through which comminuted molding material in the hopper can gravitate, the width of the hopper being a factor in determining the amount of material in a charge provided by the doser, a longitudinally grooved roller rotatably supported by the side members below and in close proximity to the elongated opening in the bottom of a hopper, a material heating roller rotatably supported by the side members and located below the grooved roller and receiving material therefrom, means for heating the material heating roller, means for removing heated material from the heating roller, means for guiding the heated material into the compression chamber of the molding machine, means for driving said rollers and means for controlling the duration of rotation of the grooved roller.

4. In the method of preparing thermosetting molding powder for briquetting, the steps comprising; feeding molding powder to a grooved roller, distributing a uniform thin layer of said molding powder from the grooved roller onto the atomare surface of a heated rotating drum, controlling the thickness of said' layer and simultaneously controlling the duration of rotation of said grooved roller whereby a predetermined quantity of molding powder is passed therethrough, carrying the relatively thin layer of molding powder onto the surface of said drum through a portion only of! the rotation thereof for a time suiilcient to bring the temperature of the molding powder to a temperature approximating the irreversible reaction temperature thereof, and then scraping the heated molding powder on. the surface of said drum.

5. For use with an injection molding machine having a compression chamber, a doser comprising a. source of supply ci comminuted molding material, a. rotating roller, and conveying means between said source and said roller for conveying a layer of comminuted material to the sui face of said roller, means for heating the roller, means for removing the heated material from the roller, for guiding the material removed from the heated roller into the' compression chamber of molding machine, means for determining thicknessA of the iayer of mate rial conveyed by said conveyor to the heated roller, and means for controlling the duration of operation of the conveying means.

6. For use with an injection molding machine having a compression chamber, a doser comprisine a source of supply of comminuted molding` material, a rotatingy roller, means for heating the roller, a moving conveyor positioned between the source of supply and the rotating roller for conveying comminuted material from the source to the roller and for depositing it upon the roller in a uniform layer, a scraper for removing heated molding material from the roller after sm'd material has been in contact with the roller a predetermined time, means for guiding the material heated by the roller and scraped therefrom into a compression' chamber of a molding machine, means for determining the thickness of the layer of material deposited on the roller by said conveyor, a power source for the roller and the conveyor, and means for disconnecting said conveyor from said power source.

CHARLES A. NICHOLS.

MAX E'. TODD.

WILLIAM A. FLETCHER.

CLARENCE J. KELLER..

'References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 208,272 Spencer Sept. 24, 1878 758,327 Maclilind Apr. 26, 1904 1,001,072 Du Pont Aug. 22, 1911 2,127,070 Pestalozza Aug. 16, 1938 2,523,670 Schueler Sept. 26, 1950 .2,525,6I3fiL Chavannes Oct. 24, 1.950 

